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The Reflections series takes a look back on historical articles from The Journal of the Acoustical Society of America that have had a significant impact on the science and practice of acoustics.

The quality of a waste paper bale depends heavily on its moisture content. The higher the moisture content, the lower the quality as a recycled resource. Therefore, accurate measurement of the moisture content of a waste paper bale is a pressing concern in the paper recycling industry. In this paper, a theoretical model for a waste paper bale, an exotic and complex medium, is developed, in which the acoustic properties of the bale are assumed to be functions of the moisture content. The model is validated through a series of impact resonance tests, which show a strong correlation between the moisture content, resonance frequencies, and the associated quality factors.

Sonoluminescence is the production of electromagnetic radiation, much of it in the form of visible light, that is emitted from a gas-filled cavity that has grown and collapsed under the influence of a varying pressure field. This resource paper provides a guide to the literature of sonoluminescence, from its early history to the present.

A composition and process suitable for making acoustic tiles are disclosed. Certain embodiments of the composition comprise: perlite; inorganic material selected from the group consisting of calcium sulfate, calcium carbonate, clay and mixtures thereof; a binder selected from the group consisting of starch, a combination of starch and cellulosic fibers, latex, kraft paper gel and mixtures thereof; optionally mineral wool; optionally gypsum; and cellulosic fiber, wherein at least a portion of the cellulosic fiber and at least a portion of the inorganic material are pulp and paper processing waste comprising cellulosic fiber, clay and calcium carbonate. Certain embodiments of the process comprise: forming an aqueous slurry; continuously flowing slurry onto a moving foraminous wire to form a cake; dewatering the cake to form a base mat; and drying the base mat.

Paper-based microfluidics have recently become a topic of interest due to the ease and low expense in fabrication, especially compared to traditional microfluidics fabrication materials, making them suitable for inexpensive diagnostics. We report a convective actuation mechanism in a simple paper-based microfluidic device using surface acoustic waves to drive mixing. Using a Y-channel structure patterned onto paper, the mixing induced by 30 MHz acoustic waves is shown to be consistent and rapid, overcoming several limitations associated with its capillary-driven passive mixing counterpart: the latter exhibits nonuniform and irreproducible mixing. Capillary-driven mixing offers only poor control, is strongly dependent on the paper's texture and fibre alignment, and permits backflow, all due to the scale of the fibres being significant in comparison to the microfluidics features. Using a novel hue-based colourimetric technique, the mixing speed and efficiency is computed. For the acoustically driven mixing ...

A method for measuring the rigidity of paper or other products made from cellulose fibers wherein the paper is torn and a digitized sound recording is made during the tearing process which is then analyzed to determine the percentage of time during which characteristic frequencies are present during the tearing process. It has been found that this percentage correlates well with rigidity.

The earliest comprehensive, in-situ measurements of the acoustic backscattering strength of the seabed as a function of frequency, grazing angle and sediment type were made by McKinney and Anderson, and published in the society’s journal in 1964. It was a landmark paper and laid the groundwork for subsequent measurements and models. It is widely referenced in books and papers where seabed scattering and sonar performance prediction are concerned. Scattering strength and sediment classification, usually quantified in terms of the mean grain diameter, were thought to be closely connected. In the laboratory, using pristine samples of sorted sand, this connection was clearly demonstrated, but in situ it was overwhelmed by other factors, such as uneven size distributions, biological activity and roughness. The underlying nature of the seabed is also reflected in the scattering strength. For the same roughness, density and sound speed, the solid/fluid model consistently overestimates the scattering strength bec...

Dose–response relationships of the sort pioneered by Schultz figure prominently in the current European noise regulation policy. A position paper developed by the Working Group on Dose‐effects (part of the EU Expert Network) reviewed a range of potential health effects, but decided that annoyance and sleep disturbance remain the most prevalent and sensitive effects of transportation noise exposure, and those for which the best data were available. A Position paper providing guidance on the dose–effect relations to be used for the assessment of numbers of people annoyed by noise from transportation sources (rail, road and air) may be found at http://europa.eu.int/comm/environment/noise/home.htm This presentation explains the context in which the Paper was developed, outlines the process by which the dose–response relationships were derived and summarizes the key recommendations. Finally some observations are made as the Position Paper is being applied, and related future developments are discussed. The author acknowledges with deep gratitude the assistance of Dr. Henk Miedema of TNO in preparing this paper.

Experiments with laser generation and detection of ultrasound in copy paper indicate that earliest arrivals of ultrasound are antisymmetric. A likely explanation is that the out-of-plane interferometer is relatively insensitive to the symmetric compressional pulse because of the low Poisson ratio of copy paper, but rather sensitive to its antisymmetric flexural wake associated with the random heterogeneities and gradients present in copy paper.

In this paper, a new method of measuring Young’s modulus in a paper cone is presented. The characteristics of this method are as follows. (1) The distribution of Young’s modulus along generatrix of the cone can be measured. (2) The technology of laser modulation is applied in this method. As a consequence, the setup of measurement has no influence on the vibration behavior. This new method has been tested and verified.

A through‐transmission, dry‐contact ultrasonic technique aimed at investigating sound propagation in the thickness direction of paper materials is presented. The method uses piezoelectric ceramic transducers immersed in fluid‐filled rubber wheels. Thickness and longitudinal velocity are determined from time domain measurements for several commercial paper specimens between 40 and 1750 μm. Dispersion and attenuation are reported at frequencies up to 1.5 MHz. Dispersion is less than 10% between 0.25 and 1.25 MHz. Amplitude calculations are used to evaluate the attenuation coefficient versus the frequency. Using a nearly local form of the Kramers–Kronig relationships, the attenuation coefficient is also obtained from the phase information. By comparing the amplitude‐ and phase‐determined attenuation coefficients, an apparent reflection coefficient is predicted. It is shown that the Kramers–Kronig relationships can be applied to papers thicker than 200 μm under dry coupling conditions. The attenuation coeffic...

Echolocation (i.e., perceiving objects using acoustic echoes) is well-known in underwater detection and to a lesser extent in robot guidance and machine perception. The paper by Tsakiris and McKerrow is concerned with machine perception in air using Freedman's asymptotic model, which was originally developed to predict the backscattering multiple-echo effect observed in sonar detection. This effect was subsequently shown to be due to the elastic response of underwater targets. Freedman's model can be used in air because the acoustic target is assumed to be rigid. Also, the model's prediction of multiple echoes can be used to obtain information about the shape of the target. This is the so-called inversion of the Freedman model by Tsakiris and McKerrow. In their paper, various simple bodies are tested in air using ultrasound and it is shown that the model provides relatively poor information about body shape. Several explanations are given. However, one explanation is not considered, namely that the model itself is not satisfactory. First, there is poor agreement with exact backscattering theory. Second, deriving information about target shape from the multiple echoes predicted by the model is a highly questionable procedure. Both these aspects are examined here.

The notebooks of Wallace Clement Sabine were discovered in 1975, and his consulting files were discovered in 1979. Both findings were reported [J. Acoust. Soc. Am. 61, 629–639 (1977); J. Acoust. Soc. Am. 69, 1–7 (1981)]. By chance, his personal papers were discovered recently and highlights from them are presented here with emphasis on his European activities from 1906 to 1917.

The following group of papers resulted from a special session entitled Speech Recognition and Perception from an Articulatory Point of View that was held during the spring 1994 meeting of the Acoustical Society of America in Cambridge, Massachusetts. Organization of the session began when Richard McGowan, Terry Nearey, and Juergen Schroeter invited speakers to give papers and critiques on the role of articulation in human perception and machine recognition. Presentations were invited from three speakers or groups of speakers who were representative of the three speech areas in the Society: production, perception, and processing. One talk was given by Bjorn Lindblom, another was given by John Ohala, and the third by Rick Rose, Juergen Schroeter, Mohan Sondhi, and Oded Ghitza. The invited critiquers for the Lindblom paper were Ken Stevens, Robert Remez, and Bishnu Atal; for the Rose et al. paper, Roger Moore, Joe Perkell, and Terry Nearey; and for the Ohala paper, Mary Beckman, Douglas O’Shaughnessy, and Carol Fowler. These people created a very interesting and provocative session. Robert Fox, associate editor of the speech perception section of the Journal, initiated publication of and edited the papers that appear here. Written versions of the invited papers are included here, as well as the critiques by Stevens, Remez, Nearey, Moore, and O’Shaughnessy. Because it was felt that Carol Fowler’s view of the importance of articulation in speech perception was not sufficiently aired in a short critique, she was asked to present her views in a longer paper.

Acoustic transmissions from a low‐frequency source near Heard Island in the southern Indian Ocean were monitored at 16 sites worldwide. The results are presented in the following papers. A summary is presented of what has been learned about the dimensions of this new subject: global acoustics.

This article reviews Collected Papers in Building Acoustics: Room Acoustics and Environmental Noise by Barry Gibbs, John Goodchild, Carl Hopkins, David Oldham , 2010. 419 pp. Price: $115.00. ISBN: 978-1-907132-14-8

Authors contemplating submitting papers to the Journal of the Acoustical Society of America (JASA) should first determine whether JASA is an appropriate journal, as it is possible that submissions for which this is not the case will be immediately rejected. A principal criterion is whether the paper will find a wider readership with JASA publication than with an alternative journal. If the appropriateness for JASA may not be manifestly obvious to the editors, then the authors should submit a cover letter explaining why, and they should write their paper so that there is a clear tie-in with articles previously published in JASA, preferably recent articles. Authors are advised to select the Associate Editor who is most likely to be familiar with the subject matter of the paper. Given that the paper is appropriate and an Associate Editor can be identified who is willing to handle the paper, it will be subsequently judged for possible acceptance based on several criteria: the most important being whether the paper is (i) original, (ii) significant, (iii) clearly written, and (iv) suitably limited in scope. The significance criterion is discussed at some length. The talk is illustrated by several disguised examples of recent submissions which were rejected.

A method for reducing the radiation amplitude of material vibration modes (division vibrations) from a loudspeaker transducer diaphragm mechanically vibrated for the purpose of transforming an electrical signal into an acoustic signal. The diaphragm material may consist of formed paper or plastic sheet materials or molded paper pulp. The amplitude reduction of material vibration modes and pressure waves within the diaphragm material is accomplished by impressing small, shaped structures within the diaphragm material at critical locations determined by measurement with laser vibration analysis or position sensitive transient analysis of a loudspeaker transducer. The method is applied to the diaphragm material after it has been formed into the shape of a loudspeaker transducer diaphragm, either before or after the diaphragm has been assembled into a loudspeaker transducer.

A Paper on the Theory of Sound.- On a Difficulty in the Theory of Sound.- On the Mathematical Theory of Sound.- The Propagation of Planar Air Waves of Finite Amplitude.- On the Thermodynamic Theory of Waves of Finite Longitudinal Disturbance.- The Life and Work of Pierre Henri Hugoniot.- On the Propagation of Motion in Bodies and in Perfect Gases in Particular -I.- On the Propagation of Motion in Bodies and in Perfect Gases in Particular - II.- Aerial Plane Waves of Finite Amplitude.- The Conditions Necessary for Discontinuous Motion in Gases.- On the Theory of Shock Waves for an Arbitrary Equation of State.- Shock Waves in Arbitrary Fluids.